Commitments and Contingencies - Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 7,100	$ 6,100	$ 9,700
Operating Leases
2018	7,287
2019	7,322
2020	6,304
2021	6,146
2022	4,923
Operating Leases, Thereafter	70
Operating Leases, Total minimum lease payments	32,052
Capital Leases
2018	19,400
2019	16,471
2020	9,567
2021	8,965
2022	8,884
Total minimum lease payments	10,014
Total minimum lease payments	73,301
Less: amount representing interest	(7,822)
Present value of future minimum lease payments	65,479
Less: current portion	(16,859)	(16,092)
Non-current portion of capital lease obligations	48,620	$ 50,213
Future minimum sublease income	$ 700